Reports until 03:05, Sunday 26 July 2015
evan.hall@LIGO.ORG -
posted 03:05, Sunday 26 July 2015 - (19935)
Some things not in the guardian
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SR3 20 Hz elliptic LPF (for M2 oplev coupling) was replaced with a more gentle 8 Hz LPF with slightly less attenuation in the stopband, but more attenuation around 20 Hz. [Attachment.] This was done without knowledge of the SR3 oplev OLTF, so it is possible we can design a more aggressive filter.
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dHard pitch gain is turned up by a factor of 2 (to 20 ct/ct), since it seems like it is able to kill that abominable 1 Hz pitch oscillation.
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cHard pitch gain turned down by 20 dB (by turning on FM1), and a 9 Hz LPF is engaged to kill angular control noise that can be seen in DARM between 10 and 20 Hz.